1. Field of the Invention
This invention relates to in-vehicle electronic apparatuses and in-vehicle electronic systems, more particular, to an electronic apparatus to which a portable navigation apparatus is attached and an electronic system therefor.
2. Description of the Related Art
As conventional navigation apparatuses, there are widely known small-sized portable navigation apparatuses with simplified structure and portability (hereinafter, referred to as Portable Navi), also known as Personal Navigation Device; and in-vehicle navigation apparatuses accommodated and fixed in a recess portion (DIN opening) formed in a dashboard of a vehicle. The in-vehicle navigation apparatuses are capable of guiding with high accuracy by use of the information supplied from vehicles such as vehicle speed, and some of the in-vehicle navigation apparatuses are equipped with audio devices.
In recent years, the navigation apparatuses with portability of the Portable Navi and high-accuracy guide function of the in-vehicle navigation apparatus have been studied.
Japanese Patent Application Publication No. 8-318792, Japanese Patent Application Publication No. 2002-328026, Japanese Patent Application Publication No. 2005-524570, and Japanese Patent Application Publication No. 2001-239895 disclose a configuration where a navigation portion can be detached from an in-vehicle apparatus mounted in a vehicle. By removing the navigation portion from the in-vehicle apparatus, the navigation portion can be used as a Portable Navi of a single unit. Also, as disclosed in Japanese Patent Application Publication No. 2003-166848, the navigation apparatus is taken out of the vehicle and can be used while walking. In addition, when mounted in a vehicle, the navigation apparatus is in a car-navigation mode, and when taken out of the vehicle, the navigation apparatus is in a person-navigation mode.
In some cases, from a detachable portable navigation apparatus to an in-vehicle electronic apparatus, the navigation audio information and music data or the like is output.
In the afore-mentioned case, audio information for navigation and that for music data or the like are sent by different connecting lines (cables or the like) from the portable navigation apparatus to the in-vehicle electronic apparatus. In this manner, since two types of audio information are sent to the in-vehicle electronic apparatus from the portable navigation apparatus, two connecting lines and two connectors are needed, impeding the reduction in size and cost. In addition, since it is enough for some of passengers to hear the navigation guidance, it may be annoying for other passengers.